1. Field of the Invention
The invention concerns a fish-based multitextured food product, a multitextured food preparation, a process for obtaining these products and a manufacturing installation for application of the process.
2. Brief Description of Related Developments
Products based on surimi and obtained after forming and cooking, such as imitation lobster tails, shrimps and crab claws, already exist.
These imitation products which resemble marine products in terms of size and shape are generally fairly large and weigh over 20 g. The manufacturing processes they undergo give them an authentic shape but not a great deal of texture.
These products have a homogeneous texture as a result of combining surimi flakes that is rather crunchy or grainy.
Moreover, various processes also exist by means of which these products are obtained, such as scarified and rolled bars, flakes produced by slicing said bars, seafood meats obtained by stacking successive layers.
These products are obtained by scarification of a strip of gelled surimi then processing this strip. The products may have a pseudo-fibrous macrostructure, as a result of shredding the strips to be made to resemble crab meat as much as possible.
This pseudo-fibrous texture cannot be regarded as being truly fibrous in the same way as natural fish or crustacean muscle.
These processes are not well adapted the production of forms other than conventional forms (bars, flakes, slices).
There are also processes in existence for the production of imitation shrimp tails by moulding a mixture of fairly large fibres and a fish paste.
Document U.S. Pat. No. 4,362,752 describes such a process in which fibres have a diameter of under 0.5 mm.
Document U.S. Pat. No. 396,634 describes such a process using fibres with diameters in the range of 0.5 to 5 mm, preferably between 1 and 3 mm.
Document U.S. Pat. No. 584,204 describes such a process using a mixture of gelled fish fibres with diameters in the range of 1 to 4 mm, preferably between 0.3 and 3 mm.
Each of these documents uses fibres within a range of specific sizes to obtain the desired type of structure, to imitate or artificially recreate the meat of crustaceans or molluscs.
The invention concerns the production, by mixing a fibrous material and a paste material, of products with varying textures, called multitextured, which resemble the texture of natural fish and crustacean muscle without totally substituting for the texture and shape of the original products.
Further, the invention is aimed at obtaining, from a given formula, a wide range of textures in multitextured products, both in terms of the size of incorporated fibres and wide range of paste material textures.
The invention is also aimed at obtaining specific and original forms of the finished product, in the order of 3 to 150 g, especially small forms weighing under 20 grams.
To this end, a first aspect of the invention concerns a fish based food product comprising two materials, a paste material and a fibrous material, the paste material being aerated by texturization, incorporating individual fibres or bundles of fibres with a diameter in the range of 1 xcexcm to 1 mm, the product presenting a heterogeneous texture and a firm and elastic overall consistency similar to that of fish or crustacean muscle tissue.
According to one embodiment, the fibrous material, obtained by extrusion cooking forms a network of macroscopic fibres whose diameters are in the order of 0.1 mm to 1 mm, ramified into microscopic fibres with diameters in the order of 1 xcexcm to 0.1 mm.
According to other embodiments, the fibrous material comprises of small fibres with a diameter of 0.1 mm to 1 mm, obtained by size reduction of a fish based preparation, or originating from natural fibres of seafood products resulting from mechanical separation of myotomes.
The product contains over 30% of marine ingredients, in particular between 30 and 60% of marine ingredients, mainly fish meat, and 25 to 40% water, in two or three-dimensional shapes such as thin strips, cylinders, fish pates or other shapes, to which colouring is added in some cases.
The shapes are typically 1 to 12 cm in length and weigh between 3 and 300 g, typically 3 to 20 g.
According to a second aspect, the invention concerns a fish based food preparation incorporating a product comprising of a fibrous material as presented above and a paste material consisting of over 30% of fish meat, the preparation being in the form of fish steaks, fish and vegetable based cakes, filled bars, quiches, thin slices, spreads, fish rillettes, small ludic shapes.
According to a third aspect, the invention concerns a process for the production of above-described heterogeneous texture products, a process comprising the following steps:
manufacture of fibrous material and paste material;
mixing the fibrous material with the paste material;
moulding the mixture to form shapes.
The paste material is textured, usually by addition of air, using homogenisation, emulsification and/or expansion and/or cutting type processes, either before mixing with the fibrous material, at a rate of 0.5 part to 1 part air per 1 part of paste material, in order to obtain a gelling strength in the order of 50 to 150 g/cm2, or after mixing with the fibrous material by adding between 0.3 and 1 part air per mixture part.
According to a first embodiment, the fibrous material consists of a ramified network of fibres obtained from minced fish meat by means of a high-temperature and high-moisture extrusion cooking process comprising of the following steps:
a) introduction of fish meat into a single screw extruder;
b) transfer of fish meat from one end to the other of the extruder barrel, adjusting the screw(s) and temperature within the barrel such that raw materials successively undergo a mixing and heating step up to a temperature of about 130xc2x0 C., followed by a melting step with an increase in temperature of the material to above 130xc2x0 C., generally between 140xc2x0 C. and 200xc2x0 C., and an increase in pressure to between 0 and 50 bars, such that plasticization of the transferred material takes place;
c) extrusion at the far end of the barrel of the material obtained after plasticization through a die adapted for texturization, shaping and cooling the material such that a product with a ramified fibrous structure is obtained.
The extruded material is cooled in the die to a temperature of 100xc2x0 C., possibly even between 80xc2x0 C. and 30xc2x0 C. This consists of an initial cooling phase in an uncooled zone in the die at the outlet of the barrel, followed by a second cooling phase in a cooled zone of the die.
The material obtained at the die outlet is cooled in a cold shower, sliced to the desired length then ground, with the extruded fibres cut by shredding, mincing, lamination, blending, homogenisation and separation such that they can be dispersed in a fish based matrix.
The extruded mixture contains between 15 and 50% of dry matter, notably 25 to 40%. The dry matter of the product consists of at least 35% of total proteins. 25 to 100% of dry matter in the extruded mixture consists of dry matter originating from fish and/or other marine products, essentially comprised of marine proteins in the form fibres of surimi extract pulp, etc. and, in some cases, other marine extracts such as fish oil, fish bone powder, crustacean shell powder, chitosane, fish collagen.
According to one embodiment, in addition to dry matter originating from fish, the dry matter in the extruded mixture contains functional milk proteins, such as whey proteins, caseins and/or caseinates, the functional milk proteins being in a dried or concentrated form.
According to one embodiment, the extruded mixture also contains egg proteins in liquid or powder form, vegetable or dairy fats, concentrated or isolated vegetable proteins, vegetable flour, starches and other complex carbohydrates, food grade hydrocolloids, spices, flavouring and colouring.
The extruded fibres are used in fresh form or preserved by physical treatment such as freezing, pasteurization or sterilisation.
According to a second embodiment, the fibrous material consists of small fibres obtained from a fish based preparation according to the following steps:
mixing the ingredients of the fish based preparation;
forming the fish based preparation;
moulding and cooking the fish based preparation to allow gelling to take place; cooling;
size reduction of the fish based preparation such as cutting or grating.
The fish based preparation used in the manufacture of small fibres comprises of over 50% washed and refined fish meat suitable for gelling, to which cryoprotectant type stabilising agents are added for freezing purposes, and a moisture content below 80%, the fish based preparation possibly enriched with gelling or thickening agents so as to obtain a gel strength of 150 to 300 g/cm2.
According to a third embodiment, the fibrous material contains cooked or raw natural fibres from crab or other marine products, obtained by mechanical separation treatment, usually using a mixer with a rotary cylinder and comb.
Prior to texturization, the paste material used in the mixture:
contains over 30% washed and refined fish meat suitable for gelling, to which cryoprotectant type stabilising agents are added for freezing purposes, and a moisture content below 80%;
and in some cases enriched with gelling or thickening agents so as to obtain a gel strength of 100 to 250 g/cm2 prior to texturization.
The level of incorporation of fibrous materials in the paste material is between 5 and 60% by weight, depending on the desired final texture, usually between 10 and 60% or 5 and 30%.
Mixing takes place at a temperature in the range of xe2x88x9210xc2x0 C. and +20xc2x0 C., typically between xe2x88x922xc2x0 C. and +6xc2x0 C.
The fibres can be the same colour as the paste material or a different colour.
The fibres are incorporated according to a statistical method, in a blender or mixing tank, or according to a dynamic method, notably in an on-line mixer.
The fibrous material mixed with the paste material consists of two types of fibres chosen from the group comprised of ramified network fibres, small fibres, natural fibres.
The melting characteristics of the textured paste material is regulated as a function of the level of fats between 0 and 50%.
The paste obtained by mixing the fibres and paste material undergoes the following steps:
forming by extrusion or moulding into two- or three-dimensional shapes or into a strip;
cooking, leading to gelling and stabilisation of the product;
cooling.
Surface colour may or may not be added to the forms obtained, either to raw forms and/or after the cooking step by spraying, depositing colour on the strip or extrusion of a coloured paste material.
According to one embodiment, the cooking step consists of a combination of a microwave cooking step and steam cooking step. Microwave cooking essentially provides rapid cooking to the core of the product so as to produce a sufficiently stable gel-like structure that is stable before cooling while steam cooking leads to the surface of the product being cooked without drying it out. Microwave cooking is carried out before or simultaneously to steam cooking.
According to a fourth aspect, the invention concerns a manufacturing installation consisting of means for the manufacture of fibrous material, means for the manufacture of paste material and means for mixture shaping.
The means for manufacturing fibrous material comprise, in the case of a first embodiment, a screw extruder with two very similar interlocking screws which rotate in the same direction or in the opposite direction inside a horizontal barrel, a filling device attached at the near end of the barrel, fitted with at least one metering device for metered flow of the mixture at a predetermined rate, an extrusion die located at the far end of said barrel, thermal treatment assembly for fine-tuning the temperature within the barrel and extrusion die, said barrel being comprising:
a first zone for supply of the product formula;
a second zone for mixing, moisturisation where this is required, and heating the material up to a core temperature of at least 130xc2x0 C.;
at least a third zone for melting, increasing the temperature of the material to over 130xc2x0 C., generally between 140 and 200xc2x0 C. and pressure of the material to between 0 and 50 bars, depending on the composition of the formula, in which protein plasticization takes place, especially of fish proteins.
The second mixing and heating zone consists of 2 to 5 units, the third melting zone comprises 1 to 3 units, with a screw length to screw diameter ratio of about 10 to 33, typically between 25 and 33.
The extrusion die includes a first uncooled zone adjacent to the near end of the screw extruder, followed by at least one cooling zone, corresponding to an alignment zone of the melted and plasticized material in the viscous state and a change-of-phase zone from the viscous to solid state.
The die is connected to the barrel by means of at least one, and typically two, adapters. The first adapter has one or two perforations through which the melted and plasticized material is extruded; the second adapter is located between the first adapter and the extrusion die and its function is to balance materiel pressure and flow rate.
The extrusion die has an internal shape that is adapted to the final product, with size parameters designed to allow cooling of the melted and plasticized material to 100xc2x0 C., possibly between 80 and 10xc2x0 C. Its inner surface has a controlled roughness in order to exert shear forces on the product during the cooling process, the combination of cooling and shear forces leading to continuous texturization of the cooled material to form fibres.